I have an old Purdy hammer double that I am trying to work up loads for using 350 - 400 gr. jacketed bullets. Anyone have any ideas or experience along these lines?

Okole,
I have a P. Webley and Son hammerless in 450x3 1/4 BPE that I worked up loads for. It has 27 inch barrels with decent bores. Depending on the twist of your barrels they may or may not stabilize the 400 grain bullets well, as the original factory loads were from 270 to 365 grains.

I had best results with Federal 215 primers and foam filler lightly compressed (I use the craft type foam and simply press the case through an appropriate thickness of foam block after charging with powder). I tried many other fillers and card wad combinations, but the foam gave much more consistent results.

With the Hornady 350 grain round nose 70 grains of IMR 4831 gives close to 1800 fps, and 80 grains gives about 1900 fps. I have gone to 85 grains for 2000 fps, but this is too hot for many black powder guns (especially the ones without a third fastener). I had to do this to get the barrels to regulate in my rifle. Another load that works well with this bullet is 65 grains of Varget at about 1800 to 1850 fps.

With 400 or 405 grain Speer, Remington, or Hornady bullets 75 grains of IMR 4831 gives over 1700 fps, and 80 grains gives over 1850 fps (once again this is too hot for some BPE rifles).

I make no claims that any of these loads will be safe in your rifle, even though they are in mine. I hope this gives you something to start with in your load development. If I can be of further help please let me know.

Good shooting,
Jim

Before you start reloading your double, I encourage you to get Graeme Wright's book; Shooting the British Double Rifle. (Midway now has it.) Lots of loads and good advice in the book. Welcome to post-graduate reloading!!!

OKOLE. FROM "SHOOTING THE BRITISH DOUBLE RIFLE", SECOND EDITION, BY GRAEME WRIGHT, HE RECOMMENDS 52GRAINS OF IMR 4198, 15GRAINS OF POLYESTER PILLOW STUFFING, AND A 350GRAIN BULLET. VELOCITY SHOWS TO BE 1860FPS AT 8.2 TONS PER SQUARE INCH. THE ORIGINAL LOAD, KYNOCH 1902 BLACK POWDER, SHOWS 10.1 TPI. I USE A SIMILAR LOAD IN MY 450 No.2 FOR A LIGHT FUN LOAD. THIS BOOK IS AVIALABLE FROM huntingtons.com . I USE THE 350GR. HORNADY ROUND NOSE.

Okole: If your Purdy is a BP-era rifle, you obviously will want to be extremely conservative using any smokeless loads, for obvious reasons. I have a Ruger No. 1 .458 Tropical reamed to .450 BP/NE Express. While I shoot a heavy load of Re 15 and the Hornady 500 grain RN, I also enjoy shooting BP loads. I can't find my chronograph notes just now, but as I recall, 110 grains of Goex FFg under a 480-grain cast slug gave about 1400 out of the short No. 1 barrel. Just remember when shooting black powder that the only mistake you can make is not putting enough powder in the case and leaving air space. Black must be slightly compressed to work well, and at the lowest pressures.